Art of removing wax from oil



Patented May 4, 1926.-

, UNITED STATES.

'HARRY r. GLA'IB Am osoan n-unansxx', F wncrrme, INDIANA, assrenons T0STANDARD OIL COMPANY, OF WHITING, INDIANA, AND GHICAGO, 'ILLINOIS, A

CORPORATION 01B INDIANA.

Am or REMOVING wax 'rnom OIL. 1

No Drawing.

lowing is a specification.

The present invention relates to the art of removing wax from lighterwax-bearing d1s tillates from mineral oils which have been subjected tolittle or no cracking or thermal decomposition during distillation. Anex ample of such an oil is that known as 34 distillate from continuousor batch fireand steam distillation of crude oil. This distillatederives its name from the 'fact that the cut forming it is started whenthe stream from the still has agravity of approximately 32 to 34 Baum.The average gravity of 34 distillate is from29 to 31 Baum.-

Lightwax-bearing, substantially un- Icracked oils of this character havehitherto not been freed from wax bv chilling and Y to be readilyfiltered-through I diluted oil. willhave ayisco'sity of 75- c- 45- fiffilter pressing by reason of the fact that the nature of the wax differsfrom that of ordinary parafiine or crystalline wax and clogs or blocksthe filter cloths of the presses. It has hence been customary, in orderto free this type of oil from wax, to subject itto'a furtherdistillation, usually with steam present in such limited quantities asto permit a considerable cracking orthermal decomposition of the oilduring its distillation. As a result of this redistillation, thecharacter of.

the wax appeared to be altered enabling it filter presses when'chilled.

We have found that oil of the character described above may be freedfrom its Wax content withoutredistillation by diluting it with .an oil,preferably substantially waxfree, of somewhat lower viscosity so thatthe onds Saybolt or lower ata temperatu of 100 F. The average viscosityof; the 34 distillate is 80 to 85 seconds Saybolt at 100 F. lrVe havefound that the most satisfactory and practical results are secured bydilution to a viscosity .of fto= seconds Saybolt andv preferably about60. After such dilution the oil may be chilled and filter-pressed in theusual manner in' accord- Appli cati on filed July 7, 1922. SerialK015733753.

ance with the cold test desired in the product. Any suitable diluent oilmay be employed; for example, pressed distillate, or

an unpressed distillate of somewhat lower viscosity, such as the 30 Baumgravity distillate from tower or coking stills having a viscosity ofabout 50 seconds Saybolt at 100 F., and the like. The presence of wax inthe diluent, for example, in the case of the last ment-ioned diluent,does not interfere with the present operation.- We may also use as adiluent the'substantially waxfree portion of distillate from the fireand steam or continuous stills just preceding the 34 distillate; forexample, we may include with the 34 distillate the cut preceding itbeginning, forexample, at about 37 Q Baum. The diluent employedis of a,

lubricating oil type; that is, of higher Specific gravity and viscositythan burning oils.

The proportion of diluent employed may vary in accordance withthe'nature. of the diluent ',and the viscosity to which it'is desired toreducethe diluted mixture. For example, when pressed distillate or towerstill distillate is employed as the diluent, from '10 to 25% may beused. The precise proportion employed does not substantially affect theeffectiveness of the filter-press operation, but is controlled by theexpense of further refining subsequent to presaing and like operations.

The diluted oil is chilled in the usual man- 3 ner, for example, to 0 or-10 ,F. and g tion of the desired lubricants in any desired manner. is sometimes found desirable, as in pressing other oils, to carry out the'filter-pressing'in two stages, chilling sa to 10 to 15 F. andfilter-pressing in the first.

stage and subsequently chilling the once- --pressed oil to. a lowertemperature, say 0 F. or -10."F. and again pressing the oil.

Weclaim:'

. no .1. The method of separating wax from lighter wax-bearing,substantially uncracked oil distillates which consists in admixing"therewith'a hydrocarbon oil-of lower viscosity and heavierthan burningoil, chilling and filter-pressing the mixture.

2. 'The method of separating wax from lighter wax-bearing, substantiallyuncracked oil distillates which consists in admixing therewith ahydrocarbon oil of lower vis- 5 cosity and heavier than burning oil inquantity suflicient to produce a mixture having a viscosity below 75seconds Saybolt at 100 F., chilling and filter-pressing the mixture. 3.The method of separating wax from 1 34 distillate which consists inadmixing therewith sufiicient lower viscosity hydrocarbon oil heavierthan burning oil to reduce its viscosity to below 75 seconds Saybolt at'100 F., chilling and filter-pressing the mixture.

4. The method of separating paraflin wax from the first wax-bearing cutfrom'the fire and steam distillation of petroleum oil which consists inincorporating in said oil s'ufficient of the cut from the distillationof petroleum 20 oil preceding the first wax bearing cut to reduce itsviscosity to below 75 seconds Saybolt at 100 F., chilling andfilter-pressing the mixture. 7

HARRY F. GLAIR. OSCAR E. BRAN SKY.

